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Abstract Purpose: Workers in many industries (oil, gas, petrochemicals, cement, steel, glass, and textile) and even at home, offices are exposed to various noises with different frequencies causing hearing and non-hearing impairments. The present study aimed to investigate the effect of noise at different frequencies on physiological responses and cognitive functions of oil drilling industry personnel and urban gas pressure reducing station. Materials and Methods: This descriptive-analytical study was conducted in 2019 with the participation of 50 employees of oil drilling rigs (low frequency noise) and city gas pressure reducing stations (high frequency noise). Physiological parameters examined included (heart rate, systolic and diastolic blood pressure, and tympanic body temperature). The participantschr('39') cognitive functions were assessed using advanced reaction timer, continuous performance and working memory tests before, during and after the activities. Also, the relationship between variables was investigated using structural equation modeling (SEM). Results: The study results indicated that was exposed to noise at high and low frequencies, physiological responses, including heart rate, systolic and diastolic blood pressure and tympanic temperature increase, and this increase was statistically significant (p

Background: In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift. Methods: This case–control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with α = 0.05. Results: The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p

Introduction: The nature of firefighters’ work is characterized by its unexpected emergencies, sleep deprivation, night shift schedules, and smoke exposure during firefighting. Methods: Eighteen firefighters were involved in simulated live-fire activities. Firefighters’ health status in terms of cardiovascular and mental conditions was checked by a physician and through reviewing their medical records. Firefighters’ cognitive functions were evaluated by visual and auditory continuous performance tests (VCPT and ACPT) and paced visual and auditory serial addition tests (PVSAT and PASAT). Results: VCPT and ACPT scores were lower after the activity relative to baseline. The results revealed that ACPT appears to be more difficult than VCPT. Also, PVSAT and PASAT scores decreased significantly after the experiment. PASAT scores following firefighting tasks experienced a more significant decline compared to those of the PVSAT. Conclusions: These findings suggest that firefighters have visual and auditory cognitive function problems following firefighting activities. In conclusion, auditory cognitive function was more influenced than the visual ability as a result of the experiment.

Background: Noise is one of the most common harmful agents in the workplace. Exposure to excessive noise can lead to complications such as cardiovascular disorders, disturbance of body hormones’ rhythm and hearing loss. This study aimed at weighing and modelling factors influencing serum cortisol and melatonin concentrations of workers that are exposed to various sound pressure levels using neural network algorithm. Methodology: A case-control design was adopted in the current research. The required data were collected from 75 industrial and mining firm staff members. They were assigned to three groups with equal sample sizes (25 workers). In developing the conceptual model in regard to variables that may affect workers’ serum cortisol and melatonin concentration, SPL, age, weight, and height were included. The influence of SPL on serum cortisol concentration as assessed in the three shifts. Moreover, radioimmunoassay (RIA) was utilized to assess serum cortisol and melatonin concentrations. Neural network algorithm was subsequently exploited to weigh and model predictor factors. IBM SPSS Modeler 18.0 was the software program used for data analysis. Results: The average cortisol concentration values for administrative, condensing, and pelletizing units respectively were 10.24 ± 2.35, 12.15 ± 3.46, and 14.91 ± 4.16μgdl. On the other hand, the average melatonin concentration values for administrative, condensing, and pelletizing units respectively were 37 ± 12.52, 34 ± 13.15, and 27 ± 9.54μgdl. According to the results of the developed model for cortisol, SPL3 (32%) and age (5%) respectively had the highest and lowest impact. On the other hand, considering the model developed for melatonin, height (27%) and SPL1 (10%) were the most and least influential factors in that order. The accuracy rates of the model were also found to be 95% for cortisol and 97% for melatonin. Conclusion: Comparing cortisol concentrations during various shifts revealed a significant reduction (from the beginning to the end of the shift) in all the three groups. Further, the rise of SPL would result in higher secretion of cortisol. Moreover, in all the three groups, the average serum melatonin concentration went up from the beginning to the middle of the shift and then declined to the end of the shift. Considering the accuracy rates of the models developed to predict hormones, neural network algorithm is a suitable and powerful tool for weighing and modelling factors influencing serum cortisol and melatonin concentrations.

Abstract Background Because of their positive impact on individuals’ performance and alertness, blue enriched white light sources are gaining popularity in households and industries. However, these sources of blue light spectrum may cause oxidative stress. On the other hand, there are no empirical studies investigating the negative effect of blue enriched white light on oxidative stress. Thus, the current study aimed at empirical assessment of the effect of such light sources on oxidative stress among night shift workers. Methods The study, which adopted a cross-sectional design, focused on 30 control room operators of a petrochemical complex. The subjects followed a shift-work schedule comprising 7 night shifts, 7 day shifts, and 7 days off. The subjects were exposed to 6500 K, 3000 K, and 17,000 K light sources (which have various degrees of blue light) during three consecutive work cycles, with each cycle lasting for 7 nights. In each light condition, three salivary measurements were conducted (at the beginning, in the middle, and at the end of the shift). The measurements were used to assess catalase (CAT), total thiol molecules (TTG), and total antioxidant capacity (TAC), and melatonin. Results The results of repeated measures ANOVA showed that there was no significant difference among various light conditions with regard to salivary biomarkers (catalase, total thiol molecules, and total antioxidant capacity). There was however a significant difference between 3000 K and 17,000 K conditions with regard to the concentration of salivary melatonin (p = 0.001). Conclusion Given that there was no significant difference among various light conditions in terms of biomarkers, it is concluded that using sources of light with high color temperature can be recommended. Nonetheless, because of the limitations of the present study (e.g. short period of intervention), it is suggested that care should be exercised in using such light sources.

Background:Thermal stress may have numerous harmful effects on human health. This study aimed at investigating thermal stress in the city of Kerman, Iran. Methods:In this descriptive-analytical study, thermal stress was assessed from 6 AM to 9 PM in 2016 using four thermal stress indices including wet-bulb globe temperature (WBGT), environmental stress index (ESI), Humidex, heat stress index (HSI), and Required Sweat Rate (SWreq). Necessary data were collected from the meteorological organization of Kerman. Pearson’s correlation coefficient and linear regression were used to examine the relationships among thermal stress indices and environmental parameters. All analyses were performed using SPSS version 22. Results: Based on the results, the highest correlation coefficients were observed between ESI and WBGT (r = 0.99), Humidex and ESI (r = 0.96), Humidex and WBGT (r = 0.97) and SWreq and HSI (r = 0.99). On the other hand, thermal stress indices had significant relationships with environmental parameters including wind speed, air temperature, and relative humidity (P < 0.05). Conclusion: All indices had strong and significant associations with one another. WBGT, HSI, and Humidex demonstrated similar thermal sensations. Furthermore, according to the obtained values of ESI, Humidex, and WBGT, people enjoy thermal comfort in all months of the year (save for January as judged by the obtained WBGT value). Thus, the climate of this city poses no threat to people’s thermal comfort.

Background: Night shift work is associated with many problems such as sleep deprivation, sleepiness, decreased cognitive performance, increased human errors, and fatigue. This study set out to measure cognitive performance, melatonin rhythms, and sleep after different consecutive night shifts (7 vs. 4) among control room operators (CORs). Methods: The participants included 60 CORs with a mean age of 30.2 years (standard deviation, 2.0) from a petrochemical complex located in Southern Iran. Cognitive performance was assessed using the n-back task and continuous performance test. To evaluate melatonin, saliva was collected and tested by enzyme-linked immunosorbent assay. To assess sleep and sleepiness, the Pittsburgh Sleep Quality Index and Karolinska Sleepiness Scale were used, respectively. Results: Individuals who worked 7 consecutive night shifts had a significantly better cognitive performance and sleep quality than those who worked 4 consecutive night shifts. However, salivary melatonin profile and sleepiness trend were not affected by shift type. Conclusion: The main duty of CORs working night shifts at the studied industry included managing safety-critical processes through complex displays; a responsibility that demands good cognitive performance and alertness. It is suggested that an appropriate number of consecutive night shifts in a rotating shift system should be planned with the ultimate aim of improving CROs performance/alertness and enhancing safety. Keywords: melatonin, night shifts, performance, sleepiness

Heat stress negatively influences human health and performance, and leading to lower efficiency in daily activities. The present study sought to examine the relationship between UTCI, other heat indices (SET, PET, PMV, PPD, and WBGT), and environmental parameters. Daily data, encompassing a 12 month period in 2016 (from 6 a.m. to 9 p.m. for each day), were retrieved from the Meteorological Organization of Kerman. The data were fed into SPSS 20, followed by conducting Pearson product moment correlation and linear regression to find the association between UTCI and other heat indices/environmental parameters. Excel 2016 was also utilized to draw the relevant diagrams. Significant correlations were detected between UTCI and other heat indices (SET, PET, PMV, and WBGT). UTCI also was measurably correlated with environmental parameters like dry temperature (P

Background: Fire service workers often implement multiple duties in the emergency conditions, with such duties being mostly conducted in various ambient temperatures. Methods: The aim of the current study was to assess the firefighters' physiological responses, information processing, and working memory prior to and following simulated firefighting activities in three different hot environments. Seventeen healthy male firefighters performed simulated firefighting tasks in three separate conditions, namely (1) low heat (LH; 29â31°C, 55â60% relative humidity), (2) moderate heat (MH; 32â34°C, 55â60% relative humidity), and (3) severe heat (SH; 35â37°C, 55â60% relative humidity). It took about 45â50 minutes for each firefighter to finish all defined firefighting activities and the paced auditory serial addition test (PASAT). Results: At the end of all the three experimental conditions, heart rate (HR) and tympanic temperature (TT) increased, while PASAT scores as a measure of information processing performance decreased relative to baseline. HR and TT were significantly higher at the end of the experiment in the SH (159.41±4.25 beats/min; 38.22±0.10°C) compared with the MH (156.59±3.77 beats/min; 38.20±0.10°C) and LH (154.24±4.67 beats/min; 38.17±0.10°C) conditions (p0.05). Nonetheless, there was a measurable difference in PASAT scores between LH and SH (p

Background: Firefighters often perform multiple emergency tasks during firefighting and life-saving operations under unknown and unpredictable conditions in hot and hostile environments. Therefore, this study examined the effect of cooling strategies on attenuating physiological and cognitive function response during simulated firefighting activities in a smoke-diving room. Methods: Each firefighter engaged in four conditions: namely (1) no cooling device; control (NC), (2) cooling gel containing menthol (CG), (3) cool vest (CV), and (4) cooling gel and cool vest (CG+CV). Cooling effects were evaluated by heart rate (HR), temporal temperature (TT), reaction time (RT), and the correct response (CR). Results: In the four experimental conditions, physiological response increased, reaction time improved, and correct response decreased after the activity relative to baseline. HR and TT were significantly lower at the end of the firefighting activity in the CG+CV (147.47 ± 4.8_bpm; 37.88 ± 0.20_○C) and CV (147.53 ± 4.67_bpm; 37.90 ± 0.22_○C) compared with the CG (153.67 ± 4.82_bpm; 38.10 ± 0.22_○C) and NC (154.4 ± 4.91_bpm; 38.11 ± 0.23_○C) conditions. RT and CR were significantly higher at the end of the activity in the CG+CV and CV compared with the CG and NC conditions. Conclusion: It is concluded that strenuous firefighting tasks have a detrimental effect on firefighters’ physiological responses and cognitive function. The findings also revealed that CV was more effective than the CG in attenuating physiological responses and cognitive function during firefighting operations. Furthermore, combining CV with CG provides no additional benefit. It is concluded that cooling the body by the use of CV offered physiological and psychological benefit for firefighters during simulated firefighting activities.

Heat is one of the harmful agents in many workplaces. The current study aimed at investigating the correlation between heat stress indices (Universal Thermal Climate Index (UTCI), wet-bulb globe temperature (WBGT), wet-bulb dry temperature (WBDT), Tropical Summer Index (TSI)) and Physiological parameters among mine workers. This cross-sectional study was conducted among workers of one of the mines located in southeast Iran in July–August 2017. Workplace environmental parameters and workers' physiological parameters were measured in thirty different ways from 10 a.m. to 2 p.m. The collected data were fed into SPSS 20 followed by conducting Pearson product moment correlation to detect the relationship between heat stress indices and workers' physiological parameters. Attempts were also made to examine the associations among heat stress indices themselves. The results of data analysis indicated that the mean scores of UTCI, WBGT, WBDT, and TSI were 34.59 ± 1.51 °C, 24.59 ± 0.62 °C, 28.37 ± 0.82 °C, and 31.51 ± 0.7 °C, respectively. On the other hand, the results of Pearson correlation revealed that UTCI and WBDT had the strongest association (r = 0.93, p 0.05). The only statistically significant correlation coefficients were recorded between skin temperature and the two indices of WBGT and TSI. According to the value obtained for UTCI, the workers were exposed to severe heat stress. However, based on WBGT value and ISO 7243 standards for an adapted person, workers were not exposed to heat stress. Keywords: Heat stress, Indices, Physiological parameters, Mine

Introduction: Assessing the work ability and factors affecting it is essential in developing strategies for preventing damages and managing risks. This study aimed to investigate the simultaneous effect of noise level and physiological strain as well as individual characteristics on the work ability. Method: The population in this cross-sectional study included workers of a rubber factory. The TES noise dosimeter was used to examine individual exposure and the electro polar RS100 was used to measure physiological strain index (PSI). Individual characteristics and the work ability index were evaluated using the WAI questionnaire and analyzed using SPSS version 19. chi-square test, pearson correlation coefficient, and one-way and multiple ANOVA were used for data analysis. Results: The final modeling showed that age, exercising period, Equivalent Continuous Sound Pressure Level (Leq), PSI and employment status had significant correlations with the work ability index (p < 0.05). The modified r2 for the obtained model was also calculated to be 0.483. Discussion and conclusion: Based on the findings, number of exercising hours, employment status, age, Leq, and psi are among the factors affecting the work ability index. Use of management and engineering controls are recommended to balance work environments exposed to noise and heat and improve the work ability index. Further, improving employment status due to creating a sense of stability and reducing stress as well as enhancing lifestyle quality can be effective in increasing the work ability index.

Introduction: Increasing population, the need for services, and industrialization of societies have led to a growing demand for shift work. Shiftwork causes several disorders, and determining the weight of each disorders is important for their prevention and treatment. Therefore, the purpose of the present study was to use Analytic Network Process (ANP) to prioritize and weigh shift work disorders among the personnel of hospitals of Kerman University of Medical Sciences. Methods: This cross-sectional, descriptive-analytical study was conducted in 2017 among 300 shift work personnel of 10 public hospitals affiliated with Kerman University of Medical Sciences. ANP was used to prioritize and weigh shift work disorders. To this end, the criteria, sub-criteria, and alternatives were initially identified. Then, shift work disorders were categorized into 7 general criteria, 20 sub-criteria, and 3 alternatives. After designing the ANP and determining the effect of each criterion on the sub-criteria, the ANP questionnaire was developed and administered among the shift work personnel, who filled it out based on ANP. Super Decisions was subsequently used to weigh and prioritize shift work disorders. Results: The results indicated that shift work disorders among the nurses included sleep disorders (0.297), psychological disorders (0.275), digestive disorders (0.137), personal life disorders (0.122), etc., in that order of weighing. With respect to the support staff, the major shift work disorders involved sleep disorders (0.252), digestive disorders (0.198), personal life disorders (0.168), and psychological disorders (0.164). Considering security personnel, the top four shift work disorders were sleep disorders (0.201), digestive disorders (0.186), psychological disorders (0.174), and personal life disorders (0.145). Conclusion: According to the findings, sleep disorders had the highest weight in the three studied groups. Moreover, the night shift had the most profound effect on shift work disorders among the personnel in the three groups. It was followed by the evening shift. Morning shift had the lowest influence on shift work disorders. Therefore, the schedules should be taken to prevent these complications in the shift workers. It is suggested that work shift complications be included in the periodic examination program and, in case of discovery of any rhythmic disorder in each shift workers, the person should not remain in the shiftwork group for some time.

In the original publication of this article [1], the corresponding author’s name ‘Mokarami Hamidreza’ should be changed to ‘Hamidreza Mokarami’.

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Heat stress is considered as a serious threat to the health and safety of workers in many industries, including petrochemical and steel. Assessment of the heat stress is important from the disease prevention point of view and also for the safety and performance of workers at workplace. Although there are many indices to evaluate the heat stress, it is hard to select an applicable index for a wide range of weather conditions. The purpose of the study was to develop an optimal index based on physiological parameters in a petrochemical industry. Materials and Methods: The study was conducted in a petrochemical industry located in Assaluyeh (south of Iran). Twenty one healthy young men at different levels of fitness and heat acclimation volunteered to participate in the study. Physiological parameters including heart rate, systolic and diastolic blood pressure, skin temperature and oral temperature were measured during the working day over two consecutive weeks. Simultaneously, we measured the climatic parameters required to calculate the wet bulb globe temperature (WBGT), required sweat rate (SWreq), and the discomfort index (DI) indices. Results: All the measurements took place on 2 sites: Kar (working place) and Paziresh (resting room). Our results showed that the mean values of indices and physiological parameters in Kar for both acclimated and unacclimated groups were significantly higher than Paziresh (P